Why do not receive registration letters of registered users in the mail?

Question

Mail server

Hello! There is a site on wordpress with installed Theme My Login plugin of the latest versions. On the registration page, when a user tries to register, an activation letter does not come to the mailbox (tried both test and gmail), although after the entered data the standard ones are shown

Registration was successful, but before you can log in, you need to confirm your e-mail address. Please check your email and follow the link in the email.

I don't see any errors. With what it can be connected?

Answer 1

Most likely, the problem is in the sending host.
Check on whose behalf the confirmation is coming from and whether their domain matches the allowed sending hostnames (SPF) of yours. This is for starters.

Answer 2

it is enough to go into the mail logs on the server and see why the mail does not reach.

Answer 3

maybe the question is a little stupid, but there is no letter in the spam folder?